<?php 

/**
* 数据链接类
*/
class Model
{
	public static $pdo;
	public $table;
	public $where='';
	public $roderBy;
	public $filed='';
	public $limit;
	
	function __construct($table=null)
	{
		$this->table = $table;
		if ($this::$pdo) {
			return;
		}else{
			$dsn = "mysql:host=".C('DB_HOST').";dbname=".C('DB_DATABASE');
			$username=C('DB_USER');
			$password=C('DB_PASSWD');
			try{
				$pdo=new Pdo($dsn,$username,$password);
			}catch(PDOException $e){
				die($e->getMessage());
			}
			$pdo->query('set names'.C('DB_CHARSET'));
			$this::$pdo=$pdo;
		}
	}
	public function queryRow($sql=null)
	{
		$result=$this::$pdo->query($sql);
		return $result->fetch(PDO::FETCH_ASSOC);
	}
	public function queryAll($sql=null)
	{
		if ($sql==null) {
			$sql = "select".$this->filed."from".$this->table."".$this->where."".$this->orderBy."".$this->limit;
		}
		$result = $this::$pdo->query($sql);
		return $result->fetchAll(PDO::FETCH_ASSOC);
	}
	public function exec($sql)
	{
		$result=$this::$pdo->exec($sql);
		return $result;
	}
	public function add($arr)
	{
		$keyStr=implode(',', array_keys($arr));
		$valuesStr=implode(',', array_values($arr));
		$sql= "insert into".$this->table."(".$keyStr.")value(".$valuesStr.")";
		return $this->exec($sql);
	}
	public function where($data)
	{
		$this->where="where".$data;
		return $this;
	}
	public function orderBy($data)
	{
		$this->orderBy="roder by".$data;
		return $this;
	}
	public function limit($data)
	{
		$this->limit="limit".$data;
		return $this;
	}
	public function filed($data)
	{
		$this->filed=$data;
		return $this;
	}

}

 ?>